Grinding machine with crushdressing attachment



July 26, 1949. F. PoLK 2,477,418

GRINDING MACHINE WITH CRUSH-DRESSING ATTACHMENT Filed June 4. 1945 2sheets-sheet 1 July 26, 1949. L. F. PoLK 2,477,418

GRINDING MACHINE WITH `CRUSHDRESS:ING ATTACHMENT Filed June 4, 1945 2Sheets/Sheet 2 6em/mls EI ll l xl III I i l I I l Iszlnz-zacx/n/asaLs//a/a g l El? I mi 8 7mm-moron,

y ATTORNEY Patented July ze, 1949v GBINDING MACHINE WITH CRUSH- DRESSINGATTACHMENT Louis F. Polk, Dayton, Ohio, assignor to The SheiiicidCorporation, Dayton, Ohio, a corporation oi' Ohio Application June 4,1945, Serial No. 599,237 7 Claims. (Cl. 125-11) This invention relatesto grinding machines Vand more particularly to means for forming orsurfacing the grinding `wheel of such a machine,

p the invention being applicable to form grinders or surface grinders orthe like. t

One object `oi the invention is the provislon, in a grinding machine, ofa grinding wheel truing device including a plurality of rotatablecrushers adapted for operation on the grinding wheel, one of thecrushers shaping the grinding wheel to approximately the desired shape,while the second crusher gives'the final or accurate form as desired. je

Another obiect of the invention is the provision, in a grinding machine,of a grinding wheel truing device. having a pair of crusher wheelscarried for simultaneous movement by holding mechanism wherebyl thecrushers can be moved in one direction to bring one of them intopressure engagement with the grinding wheel, and then be moved in asecond direction so that the rst crusheris released from the grindingwheel and the second crusher is brought into pressure engagement withthe wheel. Another object is the provision of a grinding wheel truingdevice having a movable slide mechanism on which a pair of crushersare-arranged, the crushers being so moved that one of them may bebrought into engagement with the grinding wheel and produce a crushingoperation on the wheel for a desired time interval, and at the end ofthat interval, the crushers are automatically moved in a 4direction atan angle to the direction in which they rst moved, to bring the secondcrusher into-pressure engagement with the wheel.

Another object is the provision of a crusher mechanism for a surfacegrinder or the like, in which a crusher supporting slide is slidablyarranged on a crusher supporting base and is yielding on that base whenthe base is moved to bring a crusher into an engagement with thegrinding wheel, the construction being such that after a predeterminedyielding movement of the crusher slide. a solenoid lock is automaticallyenergized to hold the crusherslide lon the base and a further controlledmovement of the crusher e slide then takes place throughout a timeinterval determined by a suitable timing mechanism.

Other objects and advantages of the invention will `be `apparent fromthe following description, the appended claims, and the accompanyingdrawing,inwhich. Fig. 1 is a perspective view of a grinding machineshowing the adaptation of the invention to surface grinders, or thelike;

Fig. 2` is a side elevation, partly in section, showing the relationshipbetween the grinding wheel and the crusher adjusting mechanism;

Fig. 3 is a top plan view of the crusher adjusti ing mechanism;

Fig. 4 is a vertical section on the line 4-4 of Fig. 3;

Fig. 5 is a vertical section on line 9 5 oi Fig. 2: v

Fig. 6 is a wiring diagram;

Fig. 7 is a timing chart showing the sequential operations that takeplace; and

Fig. 8 is a diagrammatic showing of how the grinding wheel is drivenfrom the power 'drive motor or from the auxiliary slow speed drivemotor.

Referring more particularly to the drawing. in which the. same referencenumerals are used to designate like parts in the Vdiil'erent views, 20generally represents the frame structure oi a grinding machine having arotatable grinding wheel 2i. The grinding machine may be of the typehaving a movable table 23 that reciprocates back and forth and carriesthe work past the grinding wheel, or it maybe of the character moreparticularly used in grinding threads or forms on workpieces heldbetween centers. .Any suitable mechanism such as a reversible motor 3Acan -be used to move the work supporting table 23 back and forth belowthe grinding wheel, and carry the work arranged in a suitable holder 24.At the end oi the grinding operation, or any other time itmight bedesired to true the surface of the grinding wheel. the table 23 is movedto the left beyond its normal travel stroke and brought up to apredetermined position in which the grinding wheel is spaced only alittle distance from the truing crusher.

In accordance with the present invention, a plurality of rotatablecrushers are employed to form or true the grinding wheel to its intendedshape. One of these crushers gives a preliminary truing action as thegrinding wheel and the crusher are rotated in pressure engagement withone another at suitably slow speed. The first crushing operation givesan approximation to the required shape,lth'e exact shape ofthe grindingwheel desired being produced by the second crushing operation under theaction of the second crusher while the grinding wheel and its crusherare rotated'in pressure engagement with one another. The two' crusherscan have approximately the same form and shape, it desired,

and as wear takes place on the first crusher because of its use throughlonger time periods, any change in its shape will be relativelyunimportant, since the second crusher will. give the exact shape desiredand will maintain its form over long periods of time, not being calledupon to perform the major portion of the crushing operation. If desired,a portion of the formations or curves may be given to the grinding wheelby the first crusher and other portions I the grinding wheelsubsequently formed by the second crusher. In either case, the twoCrushers act to complement one another in producing the exact shapedesired on the grinding wheel periphery.

As shown in Fig. 2, the crusher that first acts on the grinding wheel isshown at 26, and the second crusher is illustrated at 2l. These twocrushers are rotatably supported for free movement on arbors carried bythe holder 28, which is slidably carried for vertical movement on acrusher table slide 29. This slide operates horizontally on the crusherbase -30 which is fixed on the work carrying table 23 of the machine.Normally, at the start of a cycle of operation, the holder 28 is in alowered position so that the axis of the crusher 26 is horizontallyarranged from the axis of the grinding wheel 2|, with the crusherslightly spaced for the grinding wheel. This is the position at whichthe table 23 is stopped and held at the end of a normal grindingoperation on the work. Movements of the crusher then take placehorizontally and vertically by means of the mechanism that will now bedescribed.

The holder 28 is vertically adjustable along the slide 29 by means of arack 32 on the holder and a spur gear 33 which is rotatably arranged ona shaft 34 carried by'the crusher slide 29.. The gear 33 carries aclutch face 35 so it may be coupled to a rotatable clutch collar 36which is keyed to the shaft 34. The shaft is driven by an electric motor6A on the slide. The clutch collar 36 is automatically controlled by ayoke 38 moved by an arm 39 pivoted at 49 and operated in one directionor the other by solenoids 'IA and 8A as shown in Fig. 5. By closing thesolenoid 8A, the shaft 34 will be coupled to the gear 33 and the holder28 will -be raised. When the solenoid 1A is energized, the shaft 34 i-scoupled to clutch disc 4I which is fixed on a gear 42 meshing with gear44 on a vertical shaft 45. On the lower end of this shaft 45 is a worm46 turning a worm wheel 41. This worm wheel is threaded on anon-rotatable feed shaft 48 splined in the slide 29, the worm -wheelbeing held against axial movement with respect to the crusher base 30.In this way, the operation of the motor 6A can drive the feed nut 50 onshaft 48 at a regular predetermined slow speed and cause a predeterminedfeed movement of the crusher slide toward the grinding wheel. This slidemovement takes place if the feed shaft 48 is held against axial movementwith respect to the base 30, and the shaft is so held, at times, bymeans of arl electric securingmeans such vas a magnetic lock 4A, whichholds the shaft 48 securely to the base 30. When this magnetic lock isnot energized,I relative movement of the crusher slide 29 toward theright as viewed in Fig. 2 is restrained only by a spring 52 interposedbetween the end of the slide 29 and a flange on shaft 48 contacting themagnetic lock. It will be understood that as the work supporting table23 is moved to the left as viewed in Fig. 2, the crusher 20 in itslowered 75 position will engage the grinding wheel, and as thisleft-hand movement of the table continues, the spring 52 will becompressed, slide 29 being forced to the right with respect to thecrusher base 30. After a predetermined relative motion has taken placein this way, a switch arm 64 of a limit switch B carried by the crusherslide 29 will ride up an abutment 55 on the base 36 and control thislimit switch, the effect of which will be presently described. There isanother limit switch E carried -by the crusher table slide 29 in suchposition as to be operated by the holder 28 when the holder has beenraised to a predetermined position in which the crusher 2ly ishorizontally opposite the grinding wheel 2|.

During the normal grinding operation, the grinding wheel 2I is rotatedat comparatively high speed by a power drive motor IA a portion of whichis shown in Fig. 1, the motor being also diagrammatically illustrated inFig., 6, where it `is shown connected through the switch Ia which isclosed when the relay I is closed. The relay I is arranged in circuitwith a normally closed switch 2a connected throughl a stop switch 58 andstart switch 59 to the secondary 60 of a transformer that is suppliedwith current from a suitable power source 62. The switch 59 is closed incarrying out a, normal grinding operationbut should be open during thecrushing operation. For crushing, a switch 63 is closed and thisconnects through a stop switch 64 and through a normally closed limitswitch S to a relay 2. Switch S is carried by the frame 20 and istemporarily opened by a lug on the table 23 as will be later described.The relay 2, when energized, opens switch 2a to make sure the powerdrive motor IA will not operate. Relay 2 also closes two switches 2b and2c,Y one of which is a holding switch around the start switch 63 and theother connects one side of the suply line to a series of -cam operatedswitches and relay coils 3 to I0 inclusive. Switch 2c also connects anautomatic timer motor 66, through the limit switch B. The relay coils 3to III each are in series with switches controlled by cams operated bythe timing motor -66 so as to give the desired sequence of operation asillustrated in the timing diagram shown in Fig. 7.

The relay coil 8 is in series with the limit` switch E which iscontrolled by the vertical movement of holder 28 as previouslymentioned. Reiay 8 is effective, when it is energized, to open thenormally closed switch 8a in series with relay 9. A switch 3a operatedby relay 3 supplies power to the reversible electric motor 3A whichtraverses the work table 23. v Switch Illa, controlled by relay In,supplies power for the reverse operation of this motor. Switch 4acontrolled by relay 4 energizes the crusher table slide lock 4A. Switch6a. closes when relay 5 is energized and supplies power -to an auxiliarydrive motor 5A, which operates through a clutch 10 to turn the grindingwheel 2I at comparatively slow speed during the crushing operation, themain power motor iA being de-energized under these conditions. Theclutch 10 is an over-running clutch of any suitable character sodesigned that the shaft carrying the grinding wheel is turned when theauxiliary drive motor 5A is operating, at comparatively slow speed themotor 5A then turning t-he main power drive motor IA slowly. The clutch,however, over runs when the main power drive motor IA is energized andturns at comparatively high speed to turn the grinding wheel rapidly.When the main drive motor IA .5 turns the grinding wheel athigh speed.the overrunning clutch permits the slow speed drive motor IA to remainstationary. When the motor A is running the grinding wheel will beturned at a peripheral speed of about`300 feet a minute, suitable for acrushing operation. Switch 9a when energized by relay 9 energizes thecrusher holder lock 9A which is supported on a bracket 62 on the crushertable slide 28. When this is energized it electrically locks the rod I8which is fixed on the holder 28 so asto secure the holder firmly to theslide 2l.

The sequence of operations in automatically crushing the grinding wheelfirst with the preliminary crusher 2l and then with the nnishing crusher21 is as follows:A

After a predetermined number of passes across the work, the table 23moves over to a predetermi ed work loading position so that the grindingwh ch is adjacent to the crushers. When a crushing operation is desired,it is initiated from this position by closing the switch il, thefollowing operation taking place:

Relay 2 is energized, opening switch 2a so as to block out the normalgrinding motor IA. At the same time holding switch 2b is closed aroundthe starting switch il and (the normally open switch 2c is closed inseries with the relay I. Energizing relay ltcloses switch 3a andstartsthe :raverse motor 3A for the table 2l so the crusher is moved`over towards the grinding wheel.

As the crusher contacts the grinding wheel a diiferential movement ofthe crusher table 4slide 29 and the crusher base 3l takes place, spring52 being compressed. This movement first closes the limit switch B whichsets the automatic timer motor 68 in operation. When the timer isstarted, the traverse of table 23 is de-energized by opening the relay lthrough its cam operated control switch. The crusher table lock 4A isenergized locking the shaft I8 to the crusher base. AThe crusher holderlock 9A is also energized, holding the crusher roll 26 horizontallyopposite the grinding wheel. The timing motor 88 then closes the relays5 and 6, thus energizing the auxiliary drive motor 5A for the grindingwheel and energizing' the crusher adjusting motor 6A. At the same time,the shifting solenoid 1A is energized to engage the clutch collar withthe shaft 45 so as to turn the worm wheel Il. This initiates a slowpositive feed of the crusher in a horizontal direction, forcing thecrusher into the grinding wheel as the feed nut is turned.

After a predetermined amount of feed has taken piace, the relay 'I andshifting solenoid 1A are de-energized by the cam that controls the relay1, thus shifting the clutch disc to a neutral position and stopping thecrusher feed. After sumcient time has elapsed for the grinding wheel tomake about two revolutions with the crusher wheel. the spring 52, whichexpanded as crusher 28 moved away. will be contracted again as the "6eifective diameters of the two crushers is ap'- proximately the same.

When `the crusher 21 reaches a position in horizontal alignment with thegrinding wheel, the limit switch E is opened, breaking the holdingcircuit of the shifting solenoid 8A. At the same time the shiftingsolenoid 1A is energized, thus energizing the clutch disc to couple theshaft 3l to the feed screw nut l1. This causes a positive feed of thecrusher roll into the grinding wheel, since the magnetic lockingsolenoid IA is closed again by the cam switch. The cam switch for theslide locking solenoid 9A on the automatic timer is also closed duringthe time the crusher holder is being raised but cannot energize theslide locking solenoid 9A because of ythe open electric switch 8a openedby the energized relay I. Therefore, when the limit switch E is opened,breaking the circuit through the relay I, the switch 8a is closed,completing the circuit through relay 9 and causing the simultaneousenergization of solenoid 9A while the shifting solenoid IA isde-energized. same time, the auxiliary 4drive motor 5A for the grindingwheel is energized and the grinding wheel starts to rotate slowly.

After a predetermined amount of feed of the crusherslide by the crusheradjusting motor 6A energized through the closed relay 6, the motor 6A isautomatically de-energized by the automatic timer which opens thecircuit through the relay 6. At the same time the shifting solenoid 1Ais de-energized to disengage the clutch disc and shift it to a neutralposition.

After enough time has taken place for th grinding wheel to make abouttwo or three revolutions `with the crusher feed inoperative, thegrinding wheel auxiliary drive motor 5A is de` energized` bydia-energizing the relay 5. Then after enoughtime has elapsed forthegrinding wheel to come to a complete stop, the table traverse motor3A is started by the automatic timer closing the circuit through therelay III closing switch Illa, and the table then4 moves from thegrinding wheel to retract the crushers horizontally to the loadingposition of the table 23.

While the table of the grinder is being moved to the right, as justmentioned, the slide locking solenoid andthe holder locking solenoid 4Aand lA are de-energized and the automatic.' timer completes its cycle ofoperations and interrupts its own circuit. When locking solenoid 9Adeenergizes, the holder descends by the force of gravity until it isstopped in lowered position with crusher 26 opposite the grinding wheel.Even'though the timer has completed its operation and the cam switch forthe table traverse controlling relay I0 has been opened, a circuit iscompleted through the relay vIll around its cam operated switch'untilthetable 23 reaches its original position, when the holding circuit 2ais interrupted by the tripping of the limit switch S operated by thetable 23. thus completing the crushing cycle.

While the form of apparatus herein described constitutes a preferredembodiment of the invention in a form applicable to a grinding machinesuch asa surface grinder, it is to be understood that the invention isnot limited to this precise form of apparatus, and that changes may bemade therein without departing from the scope of the invention which isdefined in the appended claims.

What is claimed is:

. 1. A grinding machine having a frame and a At the said holder ismounted, a slide connection between I said holder and slide and a slideconnection between said slide and frame, means including onev of saidslide connections formoving said holder to adjust one' oi' the crushersrelatively to the grinding wheel for crushing the grinding wheel to theapproximate form desired, and means including'. the lother of said slideconnections for moving the crusher holder rectilinearly in a plane ntransverse .of the grinding wheel axis to bring the econd crusher intooperative engagement with the grinding wheel to nish the trueingoperation.

2. A grinding machine having a vframe and a grinding wheel rotatablymounted thereon,`a pair of rotatable crushers, a holder for saidcrushers,

means supporting 'said holder for rectilinear movement-towards the'grinding wheel, means supporting said holder for rectilinear movementin a direetion substantially transverse to the first direction, said twomeans comprising a slide on the frame slidably supporting said holder,means providing for yielding movement of the holder with respectto thegrinding wheel and means for operating said holder on said slide todisengage one of the crushers and cause the engagement of the secondcrdsher with the grinding wheel.

3. A grinding machine having a frame and a grinding wheel rotatablymounted thereon, a crusher holder, rotatable crushing means on saidholder for trueing the surface of the grinding wheel, means supportingsaid holder on said frame for movement in a pluralityof directionssubstantially transverse of one another, and means for moving saidholder sequentially first in one direction at a controlled rate to causeapproach of the axes of the grinding wheel and the crushing means, andthen in a second direction substantially transverse of said onedirection to gradually change the distance between the axes of thegrinding wheel and the crushing means.

4. A grinding machine having a frame and a grinding wheel rotatablymounted thereon, a pair of rotatable crushers, a crusher holder, slidevmeans slideably supporting said holder for movement in one direction ina plane transverse of the grinding wheel axis, means slideably support-Y 8 roughing crusher operable to iorm the surface of the grinding wheelto the approximate shape desired, a iinishing crusher for accuratelyfinishing the wheel after the roughing crusher has been appplied to thewheel, a common holder on which said crushers are rotatably mounted,means providing for yielding movement of said holder with respect to thegrinding wheel, and means comprising mechanical adjusting devices andelectrical control switches operable in commotion therewith forcontrolling said holder to sequentially move the roughing crusher intoyielding A pressure engagement with the wheel, then positively move theroughing crusher towards the grindingvwheel axis. then move thefinishing crusher into yielding pressure engagement with the wheel andthen positively move the nishing crusher towards the grinding wheelaxis.

6. A crusher mechanism adapted te be used to form a grinding wheelcomprising a pair of rotatable crushers, a holder for saidcrushers andslide means slidably supporting said holder. for

A@movement ina plane transverse of the crusher ing said slide means formovement in a second direction in a piane transverse of the grindingwheel axis and at a substantial angle to said rst direction, anadjusting motor carried by one of said means, drive mechanism operablyconnected to .said motor for adjusting the slide means and adjusting theholder on the slide means to vary the distance between the axes of thecrushers with respect to the grinding wheel axis, and clutch meanscontrolling said drive mechanism.

5. A grinding machine having a frame and a grinding wheel rotatablymounted thereon, a

axes in one direction generally towards the grinding wheel axis and *ina 'second direction substantially transverse of said one direction, anadjusting motor carried by said slide means, drive mechanism operablyconnected to said motor for adjsting the slide means and the holder onthe slide means, and clutch means controlling said drive mechanism tosequentially move one of the crushers into crushing engagement with thegrinding wheel and then move said crusher out of engagement with thegrinding wheel and bring ,the other crusher into crushing engagementwith the grinding wheel.

7. A crusher mechanism adapted to be used to yform a grinding Wheelcomprising a pair of rotatable crushers, a holder for said crushers andslide means slidably supporting said holder for movement in a planetransverse of the crusher axes in one direction generally towards thegrinding wheel axis and in a second direction substantially transverseof said one direction, an adjusting motor carried by said slide means,drive mechanism operably connected to said motor for adjusting the slidemeans and the holder on the slide means, means for yieldingly urging theholder towards the grinding wheel axis and lock means periodicallyoperable to overcome the action of said urging means.

LOUIS F. FOLK.

REFERENCES CITED The following referenices are of record in the file ofthis patent:

FOREIGN PATENTS

